This invention relates to a thermosetting resin system, to a process for curing thermosetting resins, to cured thermosetting foams, and to products made therefrom.
When making thermosetting resin foams it is important that the resin system possess both an attractive reactivity and favorable friability. Reactivity is usually expressed in the so-called cream time and full rise time. Generally friability of foams made by hand mixing techniques, as opposed to mechanical mixing techniques, tends to be higher, and generally not suitable for practical application. Furthermore, it is generally necessary for the heat resistancy of the foams to be high enough to evidence no distortion or collapse at temperatures up to 240.degree. C.
GB-1,474,371 discloses a heat resistant resin system comprising a polyisocyanate, an ethylenically unsaturated compound a Mannich base catalyst, and a catalytic amount of an epoxide. From the properties of the disclosed thermosetting resins, it follows that they must be free from voids. Thus the application of the disclosed resins in foamed form is not contemplated.
It is an object of the present invention to provide a foamable thermosetting resin system. It is another object of the present invention to provide thermosetting foams. It is also an object of the present invention to provide a process for curing thermosetting resin foams, and still another object of the present invention to provide thermosetting resin foams having a high heat distortion temperature, good reactivity and a favorable friability. It is still another object of this invention to provide for foamed articles.